It seems that chrome change the way it inserts hyperlinks into richt text boxes (and with chrome pretty much all other browsers). The new way is incompatible with a security feature which prevents unknown (and therefore potentially dangerous) html code to be inserted into rich text boxes.

If you have that error you can

  • open the admin client

  • hold the shift key and browse to Server Settings → [HTML Cleanup]
    Note: this setting is normally hidden that’s why you need to hold the shift key to see it

  • in there is a bit of code you can remove: noreferrer

Once this is is removed and saved it should work again.